5-Azacytidine treatment and TaPBF-D over-expression increases glutenin accumulation within the wheat grain by hypomethylating the Glu-1 promoters
- 230 Downloads
5-azaC treatment and TaPBF - D over-expression decrease C-methylation status of three Glu - 1 gene promoters, and aid in enhancing the expression of the Glu - 1 genes.
The wheat glutenins exert a strong influence over dough elasticity, but the regulation of their encoding genes has not been firmly established. Following treatment with 5-azacytidine (5-azaC), both the weight and glutenin content of the developing and mature grains were significantly increased. The abundance of transcript produced by the Glu-1 genes (encoding high-molecular-weight glutenin subunits), as well as those encoding demethylases and transcriptional factors associated with prolamin synthesis was higher than in grain of non-treated plants. These grains also contained an enhanced content of the prolamin box binding factor (PBF) protein. Bisulfite sequencing indicated that the Glu-1 promoters were less strongly C-methylated in the developing grain than in the flag leaf, while in the developing grain of 5-azaC treated plants, the C-methylation level was lower than in equivalent grains of non-treated plants. Both Glu-1 transcript abundance and glutenin content were higher in the grain set by three independent over-expressors of the D genome homoeolog of TaPBF than in the grain set by wild type plants. When assessed 10 days after flowering, the Glu-1 promoters’ methylation level was lower in the developing grains set by the TaPBF-D over-expressor than in the wild type control. An electrophoretic mobility shift assay showed that PBF-D was able to bind in vitro to the P-box of Glu-1By8 and -1Dx2, while a ChIP-qPCR analysis revealed that a lower level of C-methylation in the Glu-1By8 and -1Dx2 promoters improved the TaPBF binding. We suggest that promoter DNA C-methylation is a key determinant of Glu-1 transcription.
High-molecular-weight glutenin subunit
Low-molecular-weight glutenin subunit
Prolamin-box binding factor
Storage protein activator
GA-dependent MYB transcription factor
DNA methyltransferase homologue
This research was supported by Natural Science Foundation of China (31271706, 31471486) and Agricultural industrialization development project of high-quality seed from Shandong Province (2013). Authors thank former Prof. Robert Koebner in John Innes Centre of UK for critical comments and language improvement.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Chen F, Luo Z, Zhang Z, Xia G, Min H (2007) Variation and potential value in wheat breeding of low-molecular-weight glutenin subunit genes cloned by genomic and RT-PCR in a derivative of somatic introgression between common wheat and Agropyron elongatum. Mol Breed 20:141–152. https://doi.org/10.1007/s11032-007-9081-2 CrossRefGoogle Scholar
- Chen GX, Zhu JT, Zhou JW, Subburaj S, Zhang M, Han CX, Hao PC, Li XH, Yan YM (2014) Dynamic development of starch granules and the regulation of starch biosynthesis in Brachypodium distachyon: comparison with common wheat and Aegilops peregrina. BMC Plant Biol 14:8. https://doi.org/10.1186/s12870-014-0198-2 CrossRefGoogle Scholar
- Diaz I, Vicente-Carbajosa J, Abraham Z, Martínez M, Isabel-La Moneda I, Carbonero P (2002) The GAMYB protein from barley interacts with the DOF transcription factor BPBF and activates endosperm-specific genes during seed development. Plant J 29:453–464. https://doi.org/10.1046/j.0960-7412.2001.01230.x CrossRefPubMedGoogle Scholar
- Diaz I, Martinez M, Isabel-LaMoneda I, Rubio-Somoza I, Carbonero P (2005) The DOF protein, SAD, interacts with GAMYB in plant nuclei and activates transcription of endosperm-specific genes during barley seed development. Plant J 42:652–662. https://doi.org/10.1111/j.1365-313X.2005.02402.x CrossRefPubMedGoogle Scholar
- Flavell R, O’Dell M (1990) Variation and inheritance of cytosine methylation patterns in wheat at the high molecular weight glutenin and ribosomal RNA gene loci. Dev Suppl 1990:15–20Google Scholar
- Guo W, Yang H, Liu Y, Gao Y, Ni Z, Peng H, Xin M, Hu Z, Sun Q, Yao Y (2015) The wheat transcription factor TaGAMyb recruits histone acetyltransferase and activates the expression of a high-molecular-weight glutenin subunit gene. Plant J 84:347–359. https://doi.org/10.1111/tpj.13003 CrossRefPubMedGoogle Scholar
- Hwang YS, Ciceri P, Parsons RL, Moose SP, Schmidt RJ, Huang N (2004) The maize O2 and PBF proteins act additively to promote transcription from storage protein gene promoters in rice endosperm cells. Plant Cell Physiol 45(10):1509–1518. https://doi.org/10.1093/pcp/pch173 CrossRefPubMedGoogle Scholar
- Kondo H, Shiraya T, Wads KC, Takeno K (2007) Induction of flowering by 5-azacytidine in some plant species: relationship between the stability of photoperiodically induced flowering and flower-inducing effect of DNA demethylation. Physiol Plant 131:462–469. https://doi.org/10.1111/j.1399-3054.2007.00965.x CrossRefPubMedGoogle Scholar
- Ravel C, Fiquet S, Boudet J, Dardevet M, Vincent J, Merlino M, Michard R, Martre P (2014) Conserved cis-regulatory modules in promoters of genes encoding wheat high-molecular-weight glutenin subunits. Front Plant Sci 5:621. https://doi.org/10.3389/fpls.2014.00621 CrossRefPubMedPubMedCentralGoogle Scholar
- Shahbazian MD, Grunstein M (2007) Functions of site-specific histone acetylation and deacetylation. Annu Rev Biochem 76:75–100. https://doi.org/10.1146/annurev.biochem.76.052705.162114 CrossRefPubMedGoogle Scholar
- Solís MT, El-Tantawy AA, Cano V, Risueño MC, Testillano PS (2015) 5-azacytidine promotes microspore embryogenesis initiation by decreasing global DNA methylation, but prevents subsequent embryo development in rapeseed and barley. Front Plant Sci 6:472. https://doi.org/10.3389/fpls.2015.00472 CrossRefPubMedPubMedCentralGoogle Scholar
- Wen S, Wen N, Pang J, Langen G, Brew-Appiah RA, Mejias JH, Osorio C, Yang M, Gemini R, Moehs CP, Zemetra RS, Kogel KH, Liu B, Wang X, von Wettstein D, Rustgi S (2012) Structural genes of wheat and barley 5-methylcytosine DNA glycosylases and their potential applications for human health. Proc Natl Acad Sci USA 109:20543–20548. https://doi.org/10.1073/pnas.1217927109 CrossRefPubMedPubMedCentralGoogle Scholar